Reversing blower kiln



oooooooo 0o 1 moJ/o/oJ/No QMWM v 2 Sheets-Sheet 1 R. THELEN ET ALREVERSING BLOWER KILN Filed March 20. 1925 I I F WW \m MUOOO O O0 O0 .voooooooooo vl\ Sept. 25 1923.

INVENTORS ROLF THELEN HARRY D TIEMANN fi M: W

A TTORNEYI.

FIG, 3)

FIG. 2

D T D T D T r &5

IN VEN TORS ROLF TH ELEN ATTORNEYB.

2 Sheets-Sheet 3 HARRY D. THEMANN R THELEN ET AL REVERSING BLOWER KILN IFiled March 20. 1923 i. it v H Sept. 25, 1923.

Patented Sept. 25, 1923.

MADISON, WISCONSIN, DEDICATED, BY THE UNITED STATES OF AMERICA.

REVERSING BLOWER KILN.

Application filed March 20, 1923. Serial No. 626,419.

(TILED UNDER THE ACT OF MARCH 3, 1883, 22 STAT. L, 625.)

To all whom it may concern:

Be it known that we, ROLF THELEN and HARRY D. TIEMANN, citizens of theUmted States of America, andemployees of the Department of 'Agriculture,residing in Madison, Wisconsin (whose post-oflice address is Madison,Wisconsin), have jointly invented a new and Improved Reversing BlowerKiln.

This application is made under the act of March 3, 1883, chapter 143 (22Stat. 625), and the invention herein described and claimed may be usedby the Government of the United States,-its officers and employees, andby any person in the United States without the payment tons of anyroyalty thereon. We hereby dedicate the same to the free use of theGovernment and the people of the United States. I

Our invention consists in an improvement in the design of forcedcirculation kilns or chambers for drying and conditioning lumber orsimilar material. However, its use is not limited to wood or woodproducts. It 25 consists in the adaptation of fans of the disk type, orsimilar types, to the production of a unique internal circulation of theair and the vapor in the kiln combined with the production andregulation of the heat and the humidity within the kiln. This apparatusis illustrated in Figures 1 to 4. Figure 1 represents a cross-sectionalelevation. Figure 2 represents a lan of one of the fans with its housingan a portion of the shaft. The UK) ofthe housing is broken away to showthe fan. Figure 3 is a side elevation of one of the fans with itshousing and a portion of the shaft. The side of the housing is brokenaway to show 40 the fan. Figure 4 represents a horizontal cross-sectionof the kiln taken directly beneath the lumber-supporting platform.

The principal feature which we claim as novel and an improvement overexisting kilns is the use and arrangement of the fans within the kiln.This arrangement is such that a very fast and uniform circulation of theair and vapor through the pile of lumber may be secured and that thedirection of this movement may be reversed periodically by reversing thedirection of rotation of the fans. This improved circulation causesdrying or conditioning to take place uniformly in all portions of thelumber pile and eliminates the drying lag which occurs in kilns of typesin which the circulation is not re versible. The arrangement of the fansupon a single shaft extending throughout the length of the kiln providesa simple means of producing a brisk circulation; and the elimination ofcomparatively small ducts such as those used in external blower kilnsreduces very appreciably the work required to produce a givencirculation. The pressure required to produce the circulation iscorrespondingly small, and the disk fans operate very efficiently atthese lowpressures. It is possible, therefore, by the use of thisinvention. to produce a very great circulation of airtand vapor withinthe kiln with a small expen of power.

While the drawings indicate a narrow kiln with a series of fans mountedupon a single shaft and the description applies specifically to thisform, we do not limit ourselves to this one arrangement. It is obviousto anyone skilled in the art that several rows of fans can be used inwide kilns to produce results similar to those secured b the use of oneshaft in a narrow kiln. It is also evident that the principles of thisinvention can be carried out by locating the shaft in places other thanthe one indicated.

Any well-known means of heating the air and the Vapor in the kiln may beused in conjunction with this invention. steam pipes are used they maybe concentrated towards the center or axis of the kiln beneath thelumber-supporting platform and directly in the air current from or tothe fans. Any convenient form and arrangement of heating coils orradiators may be used.

The drawings show and the specification describes steam jet pipes forincreasing the humidity, and air inlet fines and air outlet flues withsuitable dampers for decreasing the humidity.

WVhile we show in the drawings andde. scribe in'the specificationspecific means for heating the air and vapor in the kiln and forregulating the humidity of the air in the kiln, we do not limitourselves to the arrangement described, but may make use of any othersuit-able means for accomplish ing the same purposes. While the drawingsWhen illustrate and the specification describes a specific form of flatpiled lumber with a specific type of circulation of air and vapor, we donot limit the scope of the invention to this particular form since theimprovement is equally applicable to other well-known forms of piling,such as single piles with an upwardly restricted central chimney; doublepiling wih or without chimneys in each pile; inclined piling, bothsingle track and double track; vertical piling, both single track anddouble track; and other forms.

Referring to Figures are correspondingly lettered: AA represents the fanhousings. These housings entirely surround their respective fans, andeach is provided with two ducts, one of which is bifurcated. The singleduct is arranged verticalwl y and the bifurcated one horizontally. henthe direction of the circulation of the air and vapor isdownward'through the central chimney V, the air and vapor enter thevertically arranged ducts of the housings AA. passing downwardly throughthe fans BB, and then horizontally outward through the bifurcated ducts.The arrows show the general direction of the circulation of the air andvapor throughout the kiln when the fans are rotated so as to produce anupward circulation through the central chimney. When the rotation of thefans is reversed the circulation is in the opposite direction to thatindicated. BB are the fans producing the circulation. The housings inall of the illustrations have been broken away to show the location ofthe fans. Disk fans are preferable. Any type of fan, however, in whichthe reversal of the direction of rotation of the fan produces a reversalin the direction of the air current passing through the fan can be used.C is the shaft upon which the fans are mounted. Provision is made totake care of the expansionand contraction of this shaft with changes inthe temperature in the kiln. DD are air inlet dampers used to regulateand control the amount of air entering the kiln from the outside. EE arethe heating coils. The coils illustrated in the drawing and described inthe specification are of the return bend type. We do not, however, limitourselves to this type in the claims. FF are the steam jet pipes used toincrease the. humidity of the air in the kiln. The lower palr is usedwhen the circulation of air and vapor is downward through the centralchimney V, and the upper pair is used when the circulation is in thereverse direction. G is the lumber-supporting platform. Rails and trucksor other suitable means may be used for this purpose. HH are baffies tocontrol the direction of the air circulation. II are bearings for theshaft C.

J J are curtains to assist in controlling the 1, 2, 3, and 4, whicncirculation of the air and vapor. KK are the side walls of the kiln. LLis the lumber to be dried. Mlvl are running boards to enable the kilnoperator to walk along the side passages \VVV when the kiln is loaded.They also assist in controlling the direction of the circulation. N isthe shaft pulley. 00 are air outlet dampers for controlling the amountof air being exhausted from the kiln. P is a belt passing over pulleys Nand Q. Q is the motor pulley. R is the motor which furnishes the powerto drive the fans. S is a. switch for controlling the speed anddirection of rotation of the motor armature. While the drawings show andthe specification describes an electric motor, any other suitable motoror driving means may be used. TT are air inlet flues in which thedampers DD are fitted. UU are air outlet flues in which the dampers 00are fitted. V is the central chimney in the lumber pile. While thedrawings show and the specification describes a chimney with verticalsides, chimneys of other shapes, such, for instance, as A shapedchimneys in which the cross section diminishes toward the top, may beused. WW are the side air passages which may likewise be of anywellknown form as well as of the form illustrated in the drawings anddescribed in the specification. X is a distributing duct, connecting thevertical ducts of the housing; AA with the bottom of the central chimneyV. The bottom of this duct has been broken away in Figure 4 to permitdetails of the shaft and other parts to be shown. This duct is in theform of av trough with an open top and a solid bottom except where thevertical ducts of the housings AA enter.

The operation of the kiln is briefly as follows: The lumber is placedinto the kiln, the doors and all of the dampers are closed, and themotor started. Steam is turned into the coils and one set of steam jetsis turned on. Suitable regulating devices are provided to control andregulate the supply of steam to the heating coils and the supply ofsteam to the steam jets. If it is found impossible to reduce thehumidity to the desired point with the steam jets all turned off, thedampers DD and 00 are opened to allow fresh air to enter and moist airto escape. These dampers are adjusted so that a humidity below thatdesired will be secured. The steam jets may then automatically supply asufiicient amount of steam to bring the umidity up to the desired point.If the direction of rotation of the motor, the shaft, and the fans issuch that the air and vapor pass upward through the central chimney V,the air and vapor through the lumber into the side passages WW, downwardthrough these passages, across the heatin coils, and into the bifurcatedducts of t e housings, through the will pass laterally outward.

fans, and again upward through the vertical ducts in the housings. Whenoperated in this manner the lumber near the central chimney V will drymore rapidly than that near the side passages WW. To overcome this thedirection of rotation of the fans, shaft, and motor may be reversed,thus reversing the direction of the circulation of the air and vapor sothat it is now upward in the side passages WW and downward through thecentral chimney V. This reversal may take place periodically once everytwo or three days or oftener, the exact period being determined by thecondition of the lumber in the kiln.

Having fully described the construction and operation we claim asoriginal:

1. In a dry kiln, a series of fans placed near the base of the kiln, ashaft on which the fans are mounted for rotation, means for rotatingsaid shaft in either direction to cause reversal of the circulation ofthe air and vapor in said kiln, fan housings with intake and dischargeducts, and a distributing duct.

2. In a dry kiln, a series of fans placed near the base of the kiln, a

shaft on which the fans are mounted for rotation, and means for rotatingsaid shaft in either direction to cause reversal of the circulation ofthe air and vapor in the kiln.

3. In a dry kiln, a series of fans placed near the base of the kiln, ashaft on which the fans are mounted for rotation, means for rotatingsaid shaft in either direction, damp- Ered air inlet flues and damperedair outlet ues.

4. In a dry kiln, a series of fans placed near the base of the kiln, ashaft on which the fans are mounted for rotation, means for rotatingsaid shaft in either direction, dampered air inlet flues, dampered airoutlet flues, and means for heating the kiln.

5. In a dry kiln, a series of fans placed near the base of the kiln, ashaft on which the fans are mounted for rotation, means for rotatingsaid shaft in either direction, dampered air inlet flues, dampered airoutlet flues, means for heating the kiln, and means for humidifying thekiln.

March 9, 1923.

ROLF THELEN. HARRY D. TIEMAN N.

